Various devices exist for assisting scuba divers during excursions underwater for recreation or work. Most of these devices perform functions in one of two important classes. Some of the devices perform some functions of both classes. The first class of functions is "dive computer" functions. Dive computers assist a diver by calculating and displaying information such as water depth, water temperature, and time-at-depth. Dive computers also calculate and display necessary information such as no-decompression and decompression dive limits using standard dive algorithms.
The second class of functions is data assistant/communication functions. Electronic devices in this class for use underwater include devices that display messages and generate tones under certain circumstances. For example, U.S. Pat. No. 4,563,758 to Paternostro, describes a device that is capable of displaying preprogrammed messages when a key of a keyboard is pressed, or of displaying messages typed on the keyboard. This device has disadvantages. For example, only a certain number of preprogrammed messages are available to be displayed easily by pressing a single key or button. In addition, it is not possible to formulate individualized messages without the cumbersome process of keying in the message using a small keyboard. Another disadvantage is that there is no capability to store individualized messages and recall them for reuse. It is also not possible to hand draw figures on the device.
Devices used to communicate with other divers include mechanical writing slates. Mechanical writing slates are difficult to read at depth because of the lack of available light. Mechanical writing slates also have the disadvantage of requiring that writing to be erased, or cleared from the slate surface must cleared by either a mechanical device or by manual erasure. Recently, voice acoustic transmission devices have become commercially available, but are expensive and cumbersome to use, and written messages or drawn objects cannot be displayed with these devices.
Various, specialized devices can be used by divers to perform additional function such as digital image capture, electronic boat finding and navigation. Typically, these devices are individual devices that must each be carried separately by a diver.
For scuba diving to be safe, efficient, and enjoyable, it is necessary to be able to make calculations using dive algorithms easily and to communicate effectively with dive "buddies". Currently, no device allows a diver to hand write or draw information electronically, clear or store and retrieve the information, or remotely communicate the hand drawn information to a diving buddy. Also, no device currently incorporates these functions in a single package with specialized functions such as digital image capture, boat finding and navigation.